Depending on where you park, the cache can be as little as a 15 minute hike to retrieve from the parking lot. Probably the closest parking area is the Crystal Springs parking area right off the Lynn Fells parkway. From there, you can head up the (steep!) hill along the Crystal Springs Trail.
The cache itself is a medium sized clear lock-box and contains a log and several trading items. It is located a little off the trail but still should be pretty easy to get to.